will my bunnies be warm enough???

I have got a 6x4 shed with a 2 tier hutch, the sleeping bit is at the top of the hutch which is opp the shed window.... the water bottle freezes up at nigth as its that cold in there.... Do i need to cover up the hutch with anything or will they be o.k as its minus degrees????
at the moment i have some old curtains over the front of the hutch at night.
have 2 bunnies.

Hi!

I have the exact same set up! (double height run, in a shed, facing a window)
I have the same worries as you .. . its been snowing for 4 days here in newcastle and i can see my breathe in the shed. I dont know if i should get a heater for the shed, or bring them into my spare room . .. i worry about them all the time. Looking for similar advice or comparisons

Lj

glad its not just me then they can only have have shredded newspaper and hay as i have a rex rabbit so straw hurts his feet!!!!!! i put lots in but they trampl it all down to a flat pancake!!!!!!
they noemally have a snugglesafe but i have lost it!!!!!!